Swirl sign
The swirl sign is a finding on noncontrast computed tomography in which an area of low attenuation lies within an otherwise high-attenuation (hyperattenuating) hematoma.[1] The low-attenuation region is fresh, uncoagulated blood, which is less dense than the surrounding clotted blood, and its presence indicates that the hematoma is still actively bleeding.[1][2] The sign is most often described in acute epidural (extradural) hematoma after head trauma.[3]
Recognising the swirl sign is important in radiology because it marks a hematoma that is expanding, which can raise intracranial pressure and lead to brain herniation; identifying it prompts urgent surgical evacuation.[2][3] In a surgical series of acute epidural hematomas the sign was present in about 14% of cases and was an independent predictor of poor outcome.[2] The same appearance has also been described in intracerebral hemorrhage, where it is associated with subsequent hematoma expansion.[4]
References
- 1 2 Kızılca, Ö; Öztek, A; Kesimal, U; Şenol, U (2017). "Signs in Neuroradiology: A Pictorial Review". Korean Journal of Radiology. 18 (6): 992–1004. doi:10.3348/kjr.2017.18.6.992. PMC 5639165. PMID 29089832.
- 1 2 3 Guo, C; Liu, L; Wang, B; Wang, Z (December 2017). "Swirl sign in traumatic acute epidural hematoma: prognostic value and surgical management". Neurological Sciences. 38 (12): 2111–2116. doi:10.1007/s10072-017-3121-4. PMID 28894943.
- 1 2 Zimmerman, RA; Bilaniuk, LT (September 1982). "Computed tomographic staging of traumatic epidural bleeding". Radiology. 144 (4): 809–812. doi:10.1148/radiology.144.4.7111729. PMID 7111729.
- ↑ Ng, D; Churilov, L; Mitchell, P; Dowling, R; Yan, B (February 2018). "The CT swirl sign is associated with hematoma expansion in intracerebral hemorrhage". American Journal of Neuroradiology. 39 (2): 232–237.